The effect of synthesis conditions on the physicochemical properties of magnesium aluminate materials

Magnesium aluminate-based materials were prepared by applying different methods: (i) mechanochemical milling of the initial mixture of magnesium and aluminium nitrate powders (in appropriate stoichiometric amounts) followed by heat treatment at temperatures of 650 °C and 850 °C and (ii) melting of the mixture of nitrate precursors at 240 °C followed by thermal treatment at 650 °C, 750 °C and 850 °C. The effect of synthesis method on the structure and morphology of the obtained solids was studied by using various techniques such as: nitrogen adsorption-desorption isotherms, powder XRD, IR spectroscopy and SEM. It was shown that the mechanochemical milling performed before calcination procedure leads to obtaining of nanocrystalline magnesium aluminate spinel phase at lower temperature of 650 °C in comparison with the method using thermal treatment only (at 750 °C). The obtained nanomaterials exhibit mesoporous structure.     

β21s高强度钛合金的铣削试验研究

针对一种新型的难加工钛合金材料β21s,进行了刀具磨损试验和铣削力的测量试验,对材料的切削加工性进行评价,并且给出优选结果,为实际生产提供参考。     

Potential of vibro-milling technique for preparation of electroceramic nanopowders

The potential of the vibro-milling technique as a simple method to obtain usable quantities of single-phase electroceramic powders with nanosized particles was examined. A detailed study considering the role of both milling time and firing condition on phase formation and particle size of the final product was performed. The calcination temperature for the formation of the desired phase was lower when longer milling times have been applied. More importantly, by employing an appropriate choice of the milling time and calcination condition, high purity electroceramic nanopowders have been successfully prepared with a simple solid-state reaction method.     

实现多层混合刻蚀薄膜大面积均匀的方法浅探

采用多层光刻工艺结合氩离子铣的混合刻蚀方法，刻蚀高Ｔｃ超导ＹＢａＣｕＯ／ＺｒＯ２（１００）薄膜图形，取得了较好的结果。在进行氩离子镜的工艺步骤中，使用普通氩离子铣设备（离子束斑极不均匀），但采取了一定的措施─－使被刻样品在刻蚀台座上可移动，模糊地实现了薄膜的相对＂大面积＂（直径φ≥２０ｍｍ）均匀刻蚀─－可同时刻蚀２～３片６ｍｍ×１０ｍｍ薄膜，并且被刻蚀部分表面起伏约在１０ｎｍ左右。图形样品的最小线条达２μｍ，其Ｔｃ、Ｊｃ人与刻蚀前薄膜的Ｔｃ、Ｊｃ相当，即：ＴＣ为８５～９０Ｋ，Ｊｃ～１０６Ａ／ｃｍ２（在７７Ｋ下）。     

齿轮磨前滚刀的齿形研究

本文介绍了磨前滚刀滚切齿轮的最大根切量和磨后的渐开线长度计算,并建立了数学模型。为更加直观起见,还建立了模拟滚齿的数学模型。并在实验的基础上提出了参考标准。     

液压同步剪系统的设计

本文通过对蜂窝陶瓷载体成型过程的分析，指出在其成型过程中存在的问题，提出了采用液压同步剪解决这些问题的方法。论文分析了同步剪的工作原理，给出了其液压原理图及其设计特点。     

开放式玻璃自动切割机计算机控制系统

文章介绍一种自行研制的玻璃自动切割机开放式计算机控制系统，并针对该切割机加工范围大、惯性大、动态精度要求高等特点，研究了一种智能适应型PID控制算法。现场测试表明，该系统在功能、性能和控制精度上达到或接近国外同类产品的先进水平，在系统硬件和软件的开放性上优于国外产品。文中详细介绍了该计算机控制系统的功能、系统设计、控制算法及其调试结果。     

PDC钻头在胜利油田深井钻井中的应用

胜利油田为提高深井钻井速度，试验应用了PDC钻头，结果表明，深井钻井应用PDC钻头可大幅度提高机械钻速，缩短建井周期，降低钻井成本，经济效益明显。通过大量的现场试验，扩大了PDC钻头在胜利油田的使用范围，并取得很好的效果，初步形成了PDC钻头推广应用区域模式。详细介绍了胜利油田不适用PDC钻头钻进的地层岩性，给出了钻头选型及钻井参数选择原则，并对应用效果进行了分析。     

Decision-based process planning for wire and arc additively manufactured and machined parts

The conventional manufacturing of aircraft components is based on the machining from bulk material and the buy-to-fly ratio is high. This, in combination with the often low machinability of the materials in use, leads to high manufacturing costs. To reduce the production costs for these components, a process chain was developed, which consists of an additive manufacturing process and a machining process. To fully utilize the process chain’s capabilities, an integrated process planning approach is necessary. As a result, the work sequence can be optimized to achieve the economically most suitable sequence. In this paper, a method for a joint manufacturing cost calculation and subsequent decision-based cost minimization is proposed for the wire and arc additive manufacturing (WAAM) & milling process chain. Furthermore, the parameters’ influence on the results and the magnitude of their influence are determined. These results make it possible to design an economically optimal work sequence and to automate the process planning for this process chain.     

Influence of radial and axial runouts on surface roughness in face milling with round insert cutting tools

In face milling processes, the surface quality of the machined part depends on many factors, including feed, cutting tool geometry and tool errors. In this work, a numerical model for predicting the surface profile and surface roughness as a function of these factors is presented, incorporating a random values generation algorithm that makes it possible to determine the variation in surface roughness from the values that can be adopted by tool errors. This work is focused on round insert cutting tools and the influence of tool errors such as radial and axial runouts. The results that correspond to a number of teeth equal to 4, insert diameter of 12 mm, depth of cut of 0.5 mm, cutting speed of 120 m/min and feed of 0.4–1.4 mm/rev are analysed. Milling experiments are made to verify the validity of the model and the discrepancies between the experimental and theoretical surface profiles are assumed to be a consequence of different factors such as the variation in undeformed chip thickness along the surface profile.